Ice manufacture



6, 21%., A. D. SMH-FH ICE MANUFAGTURE 4 Sheets-Sheet l INVENTOR.

Filed July 29, 1943 ART/wf? D. gSM/m/ @ga ig, 34 A, D SMITH A I ICE MANFACTURE Filed July 29, 1945 4 Sheets-$119.81', 2

, INVENTOR- ARTHUR D. swf/# Y 69 -ff A. D. sMrrl-ll ICE MANUFACTURE 4 Sheets-Sheet 4 IN V EN TOR.

Filed July 29, 1945 Patented Aug. 6, 1946 UNITED STATES PATENT OFFICE ICE MANUFACTURE Arthur D. Smith, Canton, Ohio, assigner to Barium Steel Corporation,

tion of Delaware Canton, Ohio, a corpora- Application `luly 29, 1943, Serial No. 496,564

(c1. ca -172') 4 Claims.

The invention relates to the manufacture of ice and more particularly to a method of making blocks of ice for commercial use of any desired size and weight convenient for handling and use.

Heretofore, a large number of special cans filled with water and suspended in a large tank in which cold brine is circulated have been used and required in the common practice of making blocks of ice (11 x 22" x 43) for commercial use ordinarily weighing about 300 pounds, Compressed air is forced through the water in the cans while which are relatively diminutive in size.

the freezing progresses from the outside inward to eliminate air bubbles from the ice and to center impurities and the like in the center or core of each ice block. When the freezing is nearly completed, the impure water in the center or core of each ice block is drawn off and the center core is refilled with clean water after whichthe freezing of the blocks is completed. The cans are then transferred from the large tank to a thawing station, where the ice blocks are removed from the cans and stored or shipped to the ultimate place of use.

The manufacture of commercial ice blocks in accordance with prior common practice involves a very large investment and a great deal of expensive equipment, including large brine circulation tanks, ice cans, covers for the cans, compressed air equipment, overhead cranes, thawing dump equip-ment, core pumps, core suckers, core fillers, water and air filters, brine agitators, and numerous other accessories and piping. Such equipment is in addition to the refrigerating equipment necessary for supplying brine at the proper temperature for circulation in the large tanks.

No satisfactory way has ever been provided for the manufacture of commercial ice blocks using direct expansion of the primary refrigerant-and eliminating the use of brine as an intermediate cr secondary cooling medium or refrigerant.

Also, no satisfactory way has ever been provided for the manufacture of commercial ice blocks very rapidly and with a relatively small capital investment in equipment, as compared with the investment in equipment required in conventional practice.

Moreover, no satisfactory way has ever been provided for manufacturing commercial ice blocks in Small plants at or near to the place of ultimate use of the ice, as distinguished from large central plants where the ice is made and stored and shipped at substantial cost to the place of ultimate use.

Also, no satisfactory way has ever been provided for making commercial ice blocks in a portable or mobile unit.

f without using or requiring such auxiliary equipment as overhead cranes, huge'brine circulating tanks, compressed air equipment, thawing dump equipment, core processing equipment and the like, which are required in the manufacture of ice in accordance with common practice. K

Another object of 4the present invention is to provide a method of making commercial ice blocks which greatly reduce the initial plant cost, the cost of production, and consequently the cost per ton of ice manufactured.

Also, it is an object of the present invention to provide a method of producing commercial ice blocks of purer quality than ice produced in accordance With common practice.

Further, it is an object of the present invention to provide a method of making commercial ice blocks utilizing direct expansion of the primary refrigerant and eliminating the necessity of using and circulating a large volume of brine or salt water.

Also it is an object of the present invention to provide a method of making commercial ice blocks free of air cells and foreign substances without the use of any core or sucking or aeration processing equipment` y In addition,` it is an object of the present invention to provide a method of making commercial icekblccks withv materially less freezing surface than is required in accordance with common f practice.

A further object of the present invention is to provide a method of freezing commercial ice blocks of a selected Weight in materially less time, say one-quarter toene-eighth of the time required in acccordance with common practice to produce a block of the same Weight with the same temperature of refrigerant. y

Another object of the-present inventionv is to provide a method of making commercial ice blocks, which may 'be voperated .intermittently A further object of the present invention is to` provide a method of making commercial ice blocks under conditions for obtaining a maximum` rate of heat transfer enabling quick freezing of the ice.

Also it is an object of the present invention to provide a method of making commercial ice blocks in which the freezing progresses outwardly from a plurality of central freezing zones by progressively freezing thin films of water on the outside of growing cores or cylinders of ice, as distinguished from freezing from.the outside inward to a central hollow core in accordance with common practice. f Y

Furthermore, it is an object of the present invention to provide a method of freezing commercial ice lblocks in which the water is constantly being agitated to form air free ice as the freezing progresses outward on growing cylinders of ice.

Also, it is an object of the present invention to provide -al method of freezing commercial blocks of ice in which pure ice is continuously being formed from water containing-impurities or precipitates as the freezing progresses outward on growing `cylinders rather than being trapped in the core as freezing progresses from the outside inward in accordance with common practice.

Also, it is an object of thepresent invention to provide a method of making commercial ice blocks of anyV desired weight. -Such desired weight may be selected for any installation within the range of say approximately 50 to 300 pounds. The time of freezing the blocks may be'approximately constant,other conditions being the same, irrespective of the selected weight.

Moreover, it is an objectof the present invention to provide a -methodof making commercial ice blocks in any desired time for any installation selected within therrange ofY lsay approximately two to eight hours, irrespective of the selected weight of block, other conditions being the same.

And finally, it isV an object of the present invention to provide amethod of Imanufacturing ice radically different from common practice,which is much quicker, more economical, and produces purer ice in muchless space, at a much less oost of equipmentand of ice produced therein and with much less labor, attention, power, equipment and overhead than in accorance with common or conventional practice. f.

These and other objects may be obtained by the methods'procedures, steps, and operations hereinafter described in detail, and setforthin the appendedY claims, certain steps` of which may be best understood by reference to the drawings of improved apparatus for carrying out the method, in which Figure V1 is va diagrammatic view illustrating an .installation of improved apparatus for carrying out the improved method;

Fig. ,2 is adiagrammaticview of parts ofthe ice blocks manufactured by the improved apparatus;

Fig. 4 is an end view of the freezing apparatus shown in Fig, 1;

Fig. 5 is a fragmentary longitudinal sectional view taken as on the line 5-5, Fig. 6, illustrating the improved freezing apparatus;

Fig. 6 is a sectional view taken on the line 6 5, Fig. 5; and

Fig. 7 is an enlarged View of one of the freezing pipes illustrating a portion of a block of ice formed thereon.

iSimilar numerals refer to similar parts throughout the drawings.

Referring rst to Fig. 1 wherein improved apparatus for manufacturing ice in accordance with the present invention is illustrated diagrammatically, the freezing unit is generally indicated at 8, represented by dot-dash outline. The installation may also include amotor or prime mover I0 driving a gas compressor having a hot compressed gas discharge line |2 and a gas intake line 2li. The compressor is cooled preferably by water introduced to a cooling jacket through a water intake line 29 supplied by main supply 3| and discharged through the water outlet pipe 38. Y

The hot compressed gas Vpasses along line I2 through a heat exchanger |9 for a purpose to be hereinafter described, and thence through an oil trap 2| to condenser coils or tubesl I2' in the evaporative-condenser generally indicated at 9 from whence the condensed liquid refrigerant collects in a receiving tank 34.

The condenser 9 has a pit maintained lled with water to a level 3U', supplied fromV main water supply 3| ,and drained at 3|. The water level 30 in the pit is maintained in the usual manner by a oat valve indicated at I6. -A water circulating -pump I5 is located in the condenser pit-and supplies Water fom the pit to the discharge spray pipes I5' for spraying and dropping on and around the coils or condenser tubes i2 to assist in absorbing the heat from the hot gas being condensed therein.

The condenser 9 is also provided with an irlcoming air duct I8 and an outgoing air duct Il, each of which .may be provided with a fan or blower operated by a motor 3'! or circulating air through the condenser 9 around the condenser tubes l2 to carry away the heat of condensation of the refrigerant.

The level of the liquid refrigerant in receiving tank 34 may be observed by sight glass 35 and the condensed liquid refrigerant normally passes from the receiving tank 34 to the freezing unit 8 through liquid refrigerant line I3 and automatic expansion valve I4 to freezing unit connector 54. A by-pass line I3 equipped with a valve also communicates between receiving tank 34 and freezing connector 54 for a purpose to be later described.

Expanded or spent refrigerant gas leaves the freezing unit 8 through a similar connector 54a and passes through gas return line 24 to an accumulator 2l' equipped with baffles 3B, wherein entrained refrigerant liquid is separated from the gas and collects in accumulator 21 and the Vliquid maybe returned to the freezing unit 8 through by-pass line 25. The level of liquid in the accumulator may be observed by gauge or sight glass 25. The refrigerant gas returns from accumulator` 21 through line 28 to the compressor H.

Referring particularly to Figs. 4, 5, 6 and?,

ably are cylindrical tubes.

wherein the freezing unit generally lindicated at 8 is shown in detail, the freezing unit 8 may include supports 5S for bearings 52, in which the hollow shaft 4'! is journaled. A sprocket 54 may be xed to one end of shaft 4l, and the sprocket 54' may be driven by chain belt 55, speed reducer 62, belt 63 and motor 64 for rotating hollow shaft 4l,

Shaft 4l' may be provided near each end with a partition 5l and with openings 48 adjacent the outer side of each partition. A refrigerant inlet pipe 48 insulated at El may .be mounted within one end of the hollow shaft 4l and a similar refrigerant gas outlet pipe 48" insulated at 5l may be mounted within the other end of hollow shaft 4l. Inlet connector 5d and outlet connector 54a are mounted on and connected respectively to inlet and outlet pipes 43 and 4S by stuling boxes 53.

The freezing unit B further preferably comprises an outer preferably cylindrical stationary shell or drum 8a comprising side and end walls formed by outer sheet metal walls 5l, inner sheet metal walls 58 and intervening insulation material 59.

Referring particularly tol Fig. 5, shaft 4l yis adapted to rotate within the aperture 59a formed in the left hand or inlet end wall of the stationary outer drum Se. The outlet end of shaft 4l is provided with a circular header 4l surrounded by another circular header 4e for a purpose to be later described, which headers 4t and 4i are rotatable along with shaft 4? within enlarged aperture 55h provided in the inlet end wall of outer drum 8a. I

The freezing unit also includes a rotatable multi-sided evaporator drum tb mounted on shaft 47 within the outer drum iid; and the multi-sided evaporator drum 8b includes end walls formed by outer plates 5l', inner plates 58 and intervening insulation material 59. The side walls of the multi-sided drum 8b are formed by flat plates 47. The polygonal cross sectional shape of the multi-sided evaporator drum Bb'is shown as being octagonal or eight sided, but the polygon may have more or less sides if desired.

Each plate All' is formed with a number of groups of holes 4Q, and hollow freezing tubes 4b are connected to each plate 4l communicating with each hole :i9 and project outwardly at right angles to each plate 45 generally radially of hollow shaft 4l.

Referring particularly to Fig. '7, each freezing tube 4S may be mounted in any suitable manner on the drum plates 4l. As shown, the tubes 45 are preferably inserted in holes iii and Welded to the plates 4l as at t5. The outer end of each tube 46 may be closed in any suitable or convenient manner, as by threaded plugs 45. The freezingtubes 45 are shown as being and preferl-lowever, if brine is used as a secondary refrigerant as later explained, they may have anyother desired shape in cross section, as for instance they may be square, rectangular-or oval in shape. Also,the tubes 45 may beslightly tapered. from their inner to their outer ends. Furthermore, the tubes 4t are preferably made vof copper or brass for obtaining the maximum rate of heat transfer through the walls thereof.

nel members 66, and with spaced peripherally ,extending channel membersr 6l'.

Members S3 and 61 form a seriesl of shallow rectangular projecting ledges around and segregate each group of freezing tubes 46. The outer surfaces of the channel members 56 and 61 are preferably covered with insulation material 5l). Thus, the channel members 5S and 61 form a series of circulation passages diagrammatically indicated in Figs. 2 and'3 as ingoing passages 42, cross passages 42 and outgoing passages 43. The center flange or partition 43 of each longitudinal double channel 55 serves to form the passages 4Z and 43 within each double channel 66.

Referring to Fig. 5, each flat drum plate 41' has a number of groups, such as 4, 5 or 6 groups (or more or less) of freezing tubes 46 mounted thereon; and each group of freezing tubes serves to form one block of ice, as will be later described. The several groups of freezing tubes located longitudinally on one fiat drum wall 4l" are referred to as a bank of groups.

Now referring to Figs. 3 and 4, each bank of groups has a separate circulation system within passages 42, 42 and 43. An inlet tube 68 (Fig. 3) connects the ingoing passage 42 of each bank through inlet valve 44 with circular inlet header and an outlet tube 69 connects the outgoing passage 43 of each bank through outlet valve 45 and circular outlet header 4|.

Warm liquid such as water or other heat transfer medium, may be drawn from heat exchanger i9 through warm liquid supply line 22 by liquid circulating pump 39 to flexible pipe 22', detach ably connected at 44' (Fig. 2) with a valve coupling communicating with circular inlet header n" 4E. Another flexible pipe 23 is detachably connected at 45 with a valve coupling of circular outlet header 4l and leads to warm liquid return line 23, also connected with heat exchanger I9. The level of liquid in heat exchanger I9 may be observed in sight glass 20.

The numeral I4 in Figs. 1 and 6 indicates the approximate level of liquid vrefrigerant in rotatable multi-sided evaporator drum 8b during operation; while the numeral indicates the approximate Water level within the outer drum 8a of the freezing unit. Water is supplied to the drum 8a through pipe 30 communicating with the main water supply 3l, and the drum may be drained at 32. The level 60' is preferably maintained by an overflow opening 33.

The ice blocks which form on each group of freezing tubes are diagrammatically indicated at in dot-dash lines, and may be removed in a manner to be hereinafter described by opening air-tight hinged cover 3', whence they may be transferred to a place ofV storage, shipment or use along chute 6i.

In operation, the cold liquid refrigerant, which may be ammonia or other refrigerant at the usual temperature of approximately 14 F. is introduced into the interior of the multi-sided drum 8by to maintain a liquid refrigerant levelv i4 approximately as shown in Fig. 6. Water is maintained in the outer drum 3a at the approximate level 6G'.

' The multi-sided drum 3b is lrotated and during rotation the banks of groups of freezing tubes 46 on each flat drum wall 4l" successively dip down into, pass through, and emerge from the water in the lower part of the outer drum 8a. Meanwhile, the liquid refrigeranty flows into and lls the interior of the freezing tubes 45 as each bank of groups of tubes passes through the lower approximate quarter arc of rotation of the multisided drum and as the banks of groups swing through the upper left hand quarter arc of rotation, the liquid refrigerant flows out of the freezing tubes and drains back into the interior of the multi-sided drum, accompanied by evaporation of some of the liquid refrigerant. Y

Thus, as any one freezing tube 4S completes one revolution, the liquid refrigerant ows or circulates in and out of the tube; and ideal conditions for a maximum rate of heat transfer are established because the liquid refrigerant is flowing and because the small streams thereof present a relatively large liquid surface for evaporation.

As a result of these operations, a thin film of ice commences to form around the outer surface of each freezing tube 46, under ideal conditions of heat transfer. As each tube 46 dips into the water bath and emerges from the water, a further film of water is carried out of the water bath on the outer surface of the ice forming on each tube 46,

which further film in turn freezes as the multisided drum continues to rotate. Thus, the ice freezes progressively outwardly from the surface of each freezing tube 46 by the successive freezing of thin films of water on the outside of the growing core or cylinder of ice.

Operation of the unit is continued until each ice cylinder grows in size to meet the ice cylinder on and fill out the space between adjacent freezing tubes 4S of the group, to nally form a block of ice on each group of freezing tubes 46, substantially as shown in dot-dash lines at BD in Figs. 5 and 6. The shallow projecting ledges around each group of freezing tubes 46 formed by members $5 and El, serve to segregate and separate each block of ice from the next adjacent block of ice in each bank on one flat drum wall 4l" and to also segregate the blocks of each bank from the blocks of the adjacent banks.

Meanwhile, the continuous movement of the freezing tubes 4% through the bath of water serves to agitate the water, with the result that no minute air bubbles are contained within the thin nlm of water successively picked up by each freez- :'ng tube 4E, Accordingly, cloudy ice is avoided and clear ice is formed on the freezing tubes, eliminating the necessity of using special equipment for removing entrained air from the water being frozen, as is necessary in the common practice of making ice.

Moreover, as impurities dissolved in water lower its freezing point, the thin lm of ice formed on each tube 46 during that part of its revolution when above the water is washed by the water on its immersion during the balance of the revolution and the impurities rejected to the surface of the nlm are washed off and concentrate in the water. Vlhen the impurities become so concentrated in the water as to exceed their solubilities the excess impurities precipitate to the bottom of the water bath.

If desired, a sterilizing lamp may vbe mounted within the outer drum 8a to sterilize the water therein and enable the formation of sterile ice.

When the freezing of the ice blocks is completed, the expansion valve I4 is closed, the compressor H is stopped, and valve 28 is closed. Gate valve in by-pass line I3 is then opened up wide permitting a relatively large volume of warm refrigerant liquid to flow by gravity from receiving tank 34 into the interior of multi-sided drum 8b. The liquid refrigerant in receiving drum 34 is normally at a temperature of between 8O to 100 F., and as it flows into the interior of the multi-sided drum 8b, it will warm the liquid refrigerant therein and in turn be cooled by the cold liquid refrigerant therein. Some evaporation will also take place accompanied by some lowering in temperature. However, gas pressure within the multisided drum 8b will be built up, because the gas return line 28 is closed and no gas can leave the interior of the drum. The result is that the liquid refrigerant in drum 8b will reach a temperature above freezingl Meanwhile, rotation of the multi-sided drum 8b is continued and the warm refrigerant liquid now contained therein, in circulating back and forth through the freezing pipes 46, warms and gently thaws the ice immediately contacting the outer surface of freezing tubes 4G.

When such thawing operation has progressed to a sufficient degree, the rotation of the drum 8b is stopped. One flat drum wall 41' and the bank of blocks of ice 60 thereon are located opposite to hinge cover 8 of the outer drum 8a, as shown in Fig. 6 when the drum is stopped.

The door 8a is then opened, and inlet and outlet nexible pipes 22' and 23 are connected respectively at 44 and 45' with the circular inlet and outlet headers 40 and 4I. Also inlet and outlet valves 44 and 45 for the particular bank of ice blocks opposite door 8 are opened. Circulation pump 39 is then started and the warm thawing liquid from heat exchanger i9 is circulated through pipe 22 and passages 42, 42 and 43 for the particular bank, and back through pipe 23 Vwhereby each ice block is warmed slowly and gently to thaw the ice film immediately around the corner of the block adjacent the shallow rectangular projecting ledge formed by members 66 and El.

When the contacting surfaces of the ice blocks with freezing tubes 46 and plates 41' have been sufciently thawed, the blocks 60 are removed from the freezing tubes 4S through the door 28' and may be handled down chute BI to a place of storage, use, or transportation.

Thereafter, the next bank of blocks is moved to a position opposite door 8' and. the thawing operations just described are again carried out to harvest the blocks of ice on the next bank of the multi-sided drum 8b. These operations are repeated until all of the blocks of ice have been harvested, whereupon pump 39 is stopped, flexible pipes 22' and 23' are disconnected, and a new freezing cycle is commenced.

As previously stated, if the freezing tubes 46 are slightly tapered, the thawing time for removing or harvesting the ice blocks from the freezing tubes will be shortened.

As indicated in the foregoing description, the present invention enables the manufacture of commercial ice blocks by using direct expansion of the primary refrigerant and eliminates the use of brine as an intermediate or secondary cooling medium. However, it is to be understood that the other features and advantageous results of the present invention (including rapid freezing, elimination of separate aerating equipment, purer ice formed, etc.) may be obtained, even though a brine or secondary refrigerant system is used in which the primary refrigerant is expanded to cool the brine and the brine is then passed into and circulates within the interior of the multi-sided drum 8b and the freezing tubes 46. In event that brine is used, the liquid level of the brine refrigerant within the multi-sided y drum would have to cover tube 41 so that the outgoing brine would flow out of the multi-sided drum. Y

While the spacing of the tubes of each group is not critical, the tube spacing is important from the standpoint of productiomor rate at which it is desired to produce ice. Obviously, the closer the freezing tubes 46 are to each other, the more tons of ice per day can be produced in a. unit .of given size. However, the spacing must not be too close, because the ratio of hole volume to ice in anyblock produced may be too highfor some particular use for the ice. y

The presence of the holes in the ice, where the freezing tubes 146 werelocated during formation of the ice blocks', does not detract in any manner from the usefulness of the ice, and in fact it may be beneficial in connection with certain uses for the ice. Thus, a great deal of ice is used in relatively small vquantities at isolated places, such-as for Ypacking and shipping sh and vegetables.y In suchA instances, the ice is usually crushed or broken up in small pieces and the presence of the holes in the ice blocks will assist in enabling the ice to bereadily crushed or chipped.

If the tubes are spaced, say two inches apart, four times as much ice per day can be made in the same unit under the same conditions as could be made if the freezing tube spacing were four inches apart. This is because the rate of freezing is inversely proportional to the square of the thickness of ice frozen.

Accordingly, the production desired` from any particular unit and the frequency with which the ice may be harvested, determines to a large extent, the spacing between the freezing tubes. With any given spacing of freezing tubes, the size of the block of ice formed in a given time by any group of tubes may be increased simply by increasing the number of tubes in the group while maintaining the same spacing,

'The freezing tubes 46 are preferably cylindrical tubes in order to provide the necessary strength to withstand the pressure of direct expansion refrigerating medium introduced within the tubes for freezing successive tubular ice films thereon. These tubes may be approximately 35" long where it is desired to form a standard block of ice, although the tube length may be much shorter, say 8" to 10" in length if it is desired to form ice blocks of other sizes.

The tubes may have an internal diameter of from M3 to 1; tubes having a 1/2 internal diameter being preferable. The tube wall should be as thin as possible for the particular metal from which it is formed in order to cut down power loss, but the tube wall must be thick enough to supply the necessary strength for resisting pressure. I have found that 1/2" internal diameter tubes with a TLS" wall thickness 35 long and spaced 2" apart are preferable in the ordinary installationfor rapidly making commercial ice blocks. In every instance, the tubes having dimensions within the approximate ranges specied may be characterized as slender or finger-like tubes because of their relatively small diameter with respect to their length; and the tube arrangement or grouping may be termed a porcupine arrangement.

It will be further understood that the improved freezing apparatus may be operated in accordance with the present invention, for say eight or twelve or sixteen hours a day to produce the desired quantity of ice, and the unit may be shut down for the remaining time of a twenty-four hour period or over week-ends without substantial power loss during the shut-down period, in contrast with the normal operation of commercial ice plants in accordance with conventional practice, where it is difficult to shut down .-the

freezing -equipment without substantial power loss,` and where a freezing cycle for freezing the ordinary'300 pounds commercial ice blocks is approximately forty-two hours with 14 F. brine.

It is pointed out that the ability to conne primary direct expansion refrigerant within `the multi-sided drum, the ability to use small round freezing tubes with thin walls which will withstand the internal pressure of the eXpansible refrigerant, and the ability to use the liquid refrigerant under different conditions of temperature and pressure for both freezing and sufiicie'nt. thawing to release the formed ice blocks; enables the use of direct expansion of a primary refrigerant in the manufacture of commercial ice blocks, which has heretofore been believed and considered impossible.

Accordingly, the present invention provides for -the manufacture of commercial ice blocks using direct expansion of the primary refrigerant; provides for the rapid manufacture of commercial ice blocks with a relatively small capital investment; provides for the economical manufacture of commercial ice blocks in small plants at or near to the place of ultimate use of the ice, or in portable or mobile units; provides for the manufacture of ice blocks of any desired or selected weight for any one installation; eliminates the necessity of using ice cans and attendant crane, circulating tank, compressed air, thawing, and core processing equipment and the like; provides for the manufacture of very pure ice free of air cells and foreign substances without auxiliary equipment for eliminating air and foreign substances; provides for the intermittent manufacture of commercial ice b-locks without substantial power loss during shut-down periods; and eliminates much of the equipment, labor attention, power, and overhead required for the manufacture of ice in accordance with common or conventional practice.

The new and improved apparatus for the manufacture of ice shown and described, but not claimed herein, is claimed in my copending application entitled Ice manufacturing apparatus, filed of even date herewith, Serial No. 496,565.

Having now described the features of the invention, the preferred steps used in carrying out the improved method, the advantages and results obtained by the use of .the same, and the prior art dili'iculties eliminated; the new and useful methods, steps, and operations, and reasonable mechanical equivalents thereof obvious to those skilled in the art, are set forth in the appended claims.

I claim:

1. The method of making an ice block which includes the steps of intermittently during the freezing operation immersing a group of spaced parallel tubular bodies in a bath of water, internally refrigerating the bodies, to freeze the water to form ice entirely around the exterior of each body progressively outward from the outer surface of each body until the ice formed on the group of bodies merges into one block.

2. The method of making an ice block which includes the steps of intermittently during the freezing operation immersing a tubular body in a bath of water to provide successive films of water entirely around the exterior thereof, in-

troducing liquid refrigerant at a temperature below 32 F. internally of the body to freeze successive tubular ice lms from the successive water lms between successive immersions until a Ari1 desired blockof ice is formed entirely around the exterior of the tubular body, then introducing liquid refrigerant at a temperature above 32 F. internally of the body to thaw the ice film adjacent the outer surface of the body, and then removing the ice block from the body.

3. The method of making an ice block which includes the steps of continuously moving a group of spaced parallel tubular bodies in a cirzcular path into and out of a bath of Water to provide successive films of water entirely around the exteriors of the tubular bodies and internallly refrigerating the tubular bodies to freeze the films of water to form ice entirely around the exterior of each tubular body until the ice formed ron the group of tubular bodies merges into one block.

4.The method of making an ice-block which includes the steps of intermittently during the freezing operation immersing a group of spaced parailei tubular bodies inV a bath 'of Water to provide successive lms of Water entirely'around the exterior thereof, introducing liquid refrigera-nt at a temperature below 32 F. internally of the tubular bodies to freeze successive tubular ice lms from the successive Water films between successive immersions until a desired block of ice is formed entirely around the exterior'of the tubular bodies, then introducing liquid refrigerant at a temperature above 32 F. internally of the tubular bodies to thaw the ice film adjacent the outer surfaces of the tubular bodies and then removing the ice block from the tubular bodies.

ARTHUR D. SMITH. 

